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Sweet chestnut forests occupy an important role in Italy and Europe, its resilience is often affected by aggressive pathogen attack. In the last times some chestnut wood colour aberrations have attracted attention suggesting intercorrelation with biotic attacks. The present study analyses chestnut wood from a coppice-with-standards stand in Central Italy aiming to understand the reasons for discolorations in respect to a possible effect on wood physical and mechanical character. Wood specimens with different chromatic aberrations were analysed by mechanical tests, microscopic techniques (SEM), specific density measurements, and ATR-FTIR spectroscopy. Standing trees and logs were investigated by IML-RESI. Results by SEM show as all stained wood zones correspond to mycelium presence and abnormal cell wall morphologies. No real trend was found between specific density, or compressive strength, with coloured samples, infact some test samples with colour aberrations had the highest value for specific gravity. Comparing sound wood with stained wood, the semiquantitative analysis by ATR-FTIR spectroscopy allowed to detect a change in the ratio lignin/cellulose which might be due to a white rot fungus. IML-Resi has showed wood decay symptoms at root collar in coppice standards with a decrease in amplitude at least of 30%. The results find an agreement with similar studies carried out in Spanish chestnut suggesting to indeep the analysis to investigated the geographical distribution and the impact of the damage. [ABSTRACT FROM AUTHOR]

Global climate change impacts the functioning and productivity of forest ecosystems at various spatiotemporal scales across a wide range of biomes. Although summer temperatures are considered the main driver of boreal tree growth, the importance of soil moisture availability is likely to rise with decreasing latitude and increasing warming. Here, we combine dendrochronological measurements with evidence from tree growth modeling and remote sensing to quantify the effect of climate on phenology and productivity of Scots pines (Pinus sylvestris L.) in southern Siberia. Between 1960 and 2017, pine ring widths along a latitudinal transect from 53° to 56°N were mainly controlled by the availability of summer soil moisture. This finding challenges the common belief that summer temperatures are the predominant growth control in boreal forests. Moreover, we show that earlier growing season onsets can compensate for warming-induced drought stress. Despite the phenotypic plasticity of Scots pines to adapt to warmer and drier conditions, we speculate that predicted climate change will likely exceed the species' physiological tolerance in much of Eurasia's forest-steppe by the end of the twenty-first century. [ABSTRACT FROM AUTHOR]

Forests worldwide have been recently affected by severe decline and mortality, while our understanding about forest decline across spatial scale is still limited. In this work, we study how Quercus suber trees adjust their physiology, in terms of water use efficiency and secondary growth, to pathogen-induced oak decline at the whole-tree, local and landscape scales. This work was carried out in Mediterranean mixed forests where their dominant key species Q. suber is affected by a severe decline and mortality induced by the exotic soil-borne pathogen Phytophthora cinnamomi. Significant differences were not observed between defoliated and healthy trees, either in terms of water use efficiency or growth at the whole-tree scale. We found that limiting conditions, such as low soil depth and high pathogen abundance, induced trees to higher water use efficiency at local and landscape scales. Overall our findings point out that Q. suber trees subjected to soil drought and root pathogens increase water use efficiency to some extent, while this response might not be enough for the trees to overcome the physiological stress associated with the pathogen-induced dieback. We discuss the complex way by which adult Q. suber trees physiologically respond to P. cinnamomi-induced mortality, improving our understanding of the likely consequences of chronic oak decline in the future. [ABSTRACT FROM AUTHOR]